Display device

ABSTRACT

According to one embodiment, a display device includes, a first transparent substrate having a side surface and a main surface, a first alignment film disposed along the main surface, a first transparent layer located between the first transparent substrate and the first alignment film, a second transparent substrate, a pixel electrode electrically connected to a switching element, a liquid crystal layer, and a light-emitting element opposed to the side surface. The first transparent layer overlaps a part of the pixel electrode and has a lower refractive index than the first transparent substrate.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation Application of PCT Application No.PCT/JP2019/027822, filed Jul. 12, 2019 and based upon and claiming thebenefit of priority from Japanese Patent Application No. 2018-137541,filed Jul. 23, 2018, the entire contents of all of which areincorporated herein by reference.

FIELD

Embodiments described herein relate generally to a display device.

BACKGROUND

Recently, various forms of display device have been proposed. Anillumination device including a light modulation layer containing a bulkand fine particles having optical anisotropy in a light modulationelement bonded to a light guide panel is disclosed. In another example,a light source device including a light conversion portion containing apolymer dispersed liquid crystal and converting an incident lightintensity is disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view showing one configuration example of a displaydevice DSP of the present embodiment.

FIG. 2 is a perspective view showing main parts of the display deviceDSP shown in FIG. 1.

FIG. 3 is a cross-sectional view showing one configuration example of adisplay panel PNL shown in FIG. 1.

FIG. 4 is a plan view showing one configuration example of the displaypanel PNL shown in FIG. 1.

FIG. 5 is a cross-sectional view showing one configuration example ofthe display device DSP of the present embodiment.

FIG. 6 is a cross-sectional view showing another configuration exampleof the display device DSP shown in FIG. 5.

FIG. 7 is a cross-sectional view showing another configuration exampleof the display device DSP shown in FIG. 5.

FIG. 8 is a cross-sectional view showing another configuration exampleof the display device DSP shown in FIG. 5.

FIG. 9 is a plan view showing another configuration example of atransparent layer 40 shown in FIG. 4.

FIG. 10 is a plan view showing another configuration example of thetransparent layer 40 shown in FIG. 4.

DETAILED DESCRIPTION

According to the present embodiment, there is provided a display deviceincluding: a first substrate including a first transparent substratehaving a side surface and a main surface, a first alignment filmdisposed along the main surface, and a first transparent layer locatedbetween the first transparent substrate and the first alignment film; asecond substrate including a second transparent substrate, a scanningline, a signal line crossing the scanning line, a switching elementelectrically connected to the scanning line and the signal line, and apixel electrode electrically connected to the switching element; aliquid crystal layer held between the first substrate and the secondsubstrate and containing a stripe-shaped polymer and liquid crystalmolecules; and a light-emitting element opposed to the side surface. Thefirst transparent layer overlaps a part of the pixel electrode and has alower refractive index than the first transparent substrate.

According to the present embodiment, there is provided a display deviceincluding: a first substrate including a first transparent substratehaving a side surface and a main surface, and a first alignment filmdisposed along the main surface; a second substrate including a secondtransparent substrate, a scanning line, a signal line crossing thescanning line, a switching element electrically connected to thescanning line and the signal line, a pixel electrode electricallyconnected to the switching element, a second alignment film located onthe pixel electrode, and a second transparent layer located between theswitching element and the second alignment film; a liquid crystal layerheld between the first substrate and the second substrate and containinga stripe-shaped polymer and liquid crystal molecules; and alight-emitting element opposed to the side surface. The secondtransparent layer overlaps the pixel electrode and has a lowerrefractive index than the first transparent substrate.

According to the present embodiment, there is provided a display deviceincluding a first substrate, a second substrate, a liquid crystal layerheld between the first substrate and the second substrate and containinga stripe-shaped polymer and liquid crystal molecules, a light-emittingelement, and pixels arrayed in a matrix. The first substrate includes afirst transparent substrate having a side surface opposed to thelight-emitting element, a first alignment film contacting the liquidcrystal layer, and a first transparent layer located between the firsttransparent substrate and the first alignment film. The second substrateincludes a second transparent substrate, a second alignment filmcontacting the liquid crystal layer, and a second transparent layerlocated between the second transparent substrate and the secondalignment film. The first transparent layer and the second transparentlayer are insulating layers. An installation area per pixel of the firsttransparent layer is less than an installation area per pixel of thesecond transparent layer.

Embodiments will be described hereinafter with reference to theaccompanying drawings. The disclosure is merely an example, and properchanges in keeping with the spirit of the invention, which are easilyconceivable by a person of ordinary skill in the art, come within thescope of the invention as a matter of course. In addition, in somecases, in order to make the explanation clearer, the widths,thicknesses, shapes and the like of the respective parts are illustratedschematically in the drawings, rather than as an accurate representationof what is implemented. However, such schematic illustration is merelyexemplary, and in no way restricts the interpretation of the invention.In addition, in the specification and drawings, constituent elementswhich function in the same or a similar manner to those described inconnection with preceding drawings are denoted by the same referencenumbers, and detailed explanations of them that are considered redundantare appropriately omitted.

FIG. 1 is a plan view showing one configuration example of a displaydevice DSP of the present embodiment. A first direction X, a seconddirection Y and a third direction Z are orthogonal to one another in oneexample but may cross one another at an angle other than 90 degrees. Thefirst direction X and the second direction Y correspond to directionsparallel to the main surface of a substrate constituting the displaydevice DSP, and the third direction Z corresponds to the thicknessdirection of the display device DSP. In the specification, a directionfrom a second substrate SUB2 toward a first substrate SUB1 is referredto as an upper side (or simply above), and a direction from the firstsubstrate SUB1 toward the second substrate SUB2 is referred to as alower side (or simply below). When described as “the second member abovethe first member” and “the second member below the first member”, thesecond member may be in contact with the first member or apart from thefirst member. Furthermore, an observation position where the displaydevice DSP is observed is assumed to be located on a pointing end sideof an arrow indicating the third direction Z, and viewing toward an X-Yplane defined by the first direction X and the second direction Y fromthis observation position is referred to as planar view.

In the present embodiment, a liquid crystal display device employing apolymer dispersed liquid crystal will be explained as an example of thedisplay device DSP. The display device DSP includes a display panel PNL,an IC chip 1 and a wiring board 2.

The display panel PNL includes a first substrate SUB1, a secondsubstrate SUB2, a liquid crystal layer LC and a sealant SE. The firstsubstrate SUB1 and the second substrate SUB2 are formed in a flat plateshape parallel to the X-Y plane. The first substrate SUB1 and the secondsubstrate SUB2 overlap in planar view. The first substrate SUB1 and thesecond substrate SUB2 are bonded together by the sealant SE. The liquidcrystal layer LC is held between the first substrate SUB1 and the secondsubstrate SUB2 and is sealed by the sealant SE. In FIG. 1, the liquidcrystal layer LC and the sealant SE are indicated by different hatchlines.

As enlarged and schematically shown in FIG. 1, the liquid crystal layerLC includes a polymer dispersed liquid crystal containing a polymer 31and liquid crystal molecules 32. In one example, the polymer 31 is aliquid crystal polymer. The polymer 31 is formed in a stripe shapeextending along the first direction X. The liquid crystal molecules 32are dispersed in gaps of the polymer 31, and are aligned such that majoraxes of them extend along the first direction X. The polymer 31 and theliquid crystal molecule 32 each have optical anisotropy or refractiveanisotropy. The responsiveness to an electric field of the polymer 31 isless than the responsiveness to an electric field of the liquid crystalmolecule 32.

In one example, the alignment direction of the polymer 31 hardly changesregardless of the presence or absence of an electric field. On the otherhand, the alignment direction of the liquid crystal molecule 32 changesin accordance with an electric field in a state where a high voltage ofgreater than or equal to a threshold value is applied to the liquidcrystal layer LC. In a state where voltage is not applied to the liquidcrystal layer LC, the optical axis of the polymer 31 and the opticalaxis of the liquid crystal molecule 32 are parallel to each other, andlight entering the liquid crystal layer LC is transmitted almost withoutbeing scattered in the liquid crystal layer LC (transparent state). In astate where voltage is applied to the liquid crystal layer LC, theoptical axis of the polymer 31 and the optical axis of the liquidcrystal molecule 32 cross each other, and light entering the liquidcrystal layer LC is scattered in the liquid crystal layer LC (scatteringstate).

The display panel PNL includes a display portion DA which displays animage and a frame-shaped non-display portion NDA which surrounds thedisplay portion DA. The sealant SE is located in the non-display portionNDA. The display portion DA includes pixels PX arrayed in a matrix inthe first direction X and the second direction Y.

As shown enlarged in FIG. 1, each pixel PX includes a switching elementSW, a pixel electrode PE, a common electrode CE, the liquid crystallayer LC and the like. The switching element SW is composed of, forexample, a thin-film transistor (TFT) and is electrically connected to ascanning line G and a signal line S. The scanning line G is electricallyconnected to the switching elements SW in the respective pixels PXdisposed in the first direction X. The signal line S is electricallyconnected to the switching elements SW in the respective pixels PXdisposed in the second direction Y. The pixel electrode PE iselectrically connected to the switching element SW. Each pixel electrodePE is opposed to the common electrode CE and drives the liquid crystallayer LC (in particular, the liquid crystal molecules 32) by an electricfield generated between the pixel electrode PE and the common electrodeCE. A capacitance CS is formed, for example, between an electrode havingthe same potential as the common electrode CE and an electrode havingthe same potential as the pixel electrode PE.

The second substrate SUB2 has an extension portion Ex. In theillustrated example, the extension portion Ex correspond to a region inwhich the second substrate SUB2 does not overlap the first substrateSUB1.

The IC chip 1 and the wiring board 2 are each connected to the extensionportion Ex. The IC chip 1 has, for example, a built-in display driverwhich outputs a signal necessary for image display, and the like. Thewiring board 2 is a bendable flexible printed circuit board. Note thatthe IC chip 1 may be connected to the wiring board 2. The IC chip 1 andthe wiring board 2 read a signal from the display panel PNL in somecases but mainly function as a signal source which supplies a signal tothe display panel PNL.

FIG. 2 is a perspective view showing main parts of the display deviceDSP shown in FIG. 1. The display device DSP includes a plurality oflight-emitting elements LD in addition to the display panel PNL.

The first substrate SUB1 and the second substrate SUB2 includetransparent substrates 10 and 20, respectively. The transparentsubstrates 10 and 20 have side surfaces E11 and E21, respectively. Theside surfaces E11 and E21 extend along the first direction X and do notoverlap in the third direction Z. The extension portion Ex extends alongthe second direction Y between the side surface E11 and the side surfaceE21. The light-emitting elements LD are disposed at intervals in thefirst direction X and are opposed to the side surface E11. In theillustrated example, the light-emitting elements LD overlap theextension portion Ex. The light-emitting elements LD are connected to awiring board F. The light-emitting element LD is, for example, alight-emitting diode. Although not described in detail, thelight-emitting element LD includes a red light-emitting portion, a greenlight-emitting portion and a blue light-emitting portion. Light emittedfrom the light-emitting element LD travels along the direction of anarrow indicating the second direction Y.

FIG. 3 is a cross-sectional view showing one configuration example ofthe display panel PNL shown in FIG. 1. Here, a cross section of an X-Zplane defined by the first direction X and the third direction Z will beexplained.

The second substrate SUB2 includes the transparent substrate 20,insulating films 21 and 22, a capacitance electrode 23, the switchingelement SW, the pixel electrode PE, a transparent layer 30 and analignment film AL2. The second substrate SUB2 further includes thescanning line G and the signal line S shown in FIG. 1. The transparentsubstrate 20 includes a main surface (lower surface) 20A and a mainsurface (upper surface) 20B on an opposite side to the main surface 20A.The main surfaces 20A and 20B are surfaces substantially parallel to theX-Y plane. The switching element SW is disposed on the main surface 20B.The insulating film 21 covers the switching element SW. The capacitanceelectrode 23 is located between the insulating films 21 and 22. On theinsulating film 22, the pixel electrode PE is disposed for each pixelPX. The pixel electrode PE is electrically connected to the switchingelement SW via an opening OP of the capacitance electrode 23. The pixelelectrode PE overlaps the capacitance electrode 23 across the insulatingfilm 22 and forms the capacitance CS of the pixel PX. The transparentlayer 30 is continuously disposed without interruption along the firstdirection X and covers the pixel electrodes PE. The alignment film AL2covers the transparent layer 30. In the illustrated example, thetransparent layer 30 is disposed over the entire region of the pixel PX,is located between the pixel electrode PE and the alignment film AL2,and is in contact with both the pixel electrode PE and the alignmentfilm AL2. In addition, between the pixel electrodes PE which areadjacent to each other in the first direction X, the transparent layer30 is in contact with the insulating film 22. Note that anotherinsulating layer or another conductive layer may be disposed between thetransparent layer 30 and the pixel electrode PE and between thetransparent layer 30 and the alignment film AL2. In addition, thetransparent layer 30 is not limited to the illustrated example but onlyhas to be located between the transparent substrate 20 and the alignmentfilm AL2 or between the switching element SW and the alignment film AL2.

The first substrate SUB1 includes the transparent substrate 10, alight-shielding layer BM, the common electrode CE, a transparent layer40 and an alignment film AL1. The transparent substrate 10 comprises amain surface (lower surface) 10A and a main surface (upper surface) 10Bon an opposite side to the main surface 10A. The main surfaces 10A and10B are surfaces substantially parallel to the X-Y plane. The mainsurface 10A of the transparent substrate 10 faces the main surface 20Bof the transparent substrate 20. The light-shielding layer BM and thecommon electrode CE are disposed on the main surface 10A. Thelight-shielding layer BM is located, for example, directly above theswitching element SW and directly above the scanning line G and thesignal line S which are not shown in the drawing. The common electrodeCE is disposed over the pixels PX and directly covers thelight-shielding layer BM. The common electrode CE is electricallyconnected to the capacitance electrode 23 has the same potential as thecapacitance electrode 23. The transparent layer 40 is disposed in a partbelow the common electrode CE and overlaps a part of the pixel electrodePE. The alignment film AL1 covers the transparent layer 40 and coversthe common electrode CE in a part in which the transparent layer 40 isnot disposed. In the illustrated example, in a region on the right sideof the pixel PX, the transparent layer 40 is located between the commonelectrode CE and the alignment film AL1 and is in contact with both thecommon electrode CE and the alignment film AL1. Note that anotherinsulating layer or another conductive layer may be disposed between thetransparent layer 40 and the common electrode CE and between thetransparent layer 40 and the alignment film AL1. In addition, thetransparent layer 40 is not limited to the illustrated example but onlyhas to be located between the transparent substrate 10 and the alignmentfilm AL1.

The liquid crystal layer LC is located between the first substrate SUB1and the second substrate SUB2 and is in contact with the alignmentsfilms AL1 and AL2.

The transparent substrates 10 and 20 are insulating substrates such asglass substrates or plastic substrates. The insulating film 21 is formedof a transparent insulating material such as silicon oxide, siliconnitride, silicon oxynitride or acrylic resin. In one example, theinsulating film 21 includes an inorganic insulating film and an organicinsulating film. The insulating film 22 is an inorganic insulating filmof silicon nitride or the like. The capacitance electrode 23, the pixelelectrode PE and the common electrode CE are transparent electrodesformed of a transparent conductive material such as indium tin oxide(ITO) or indium zinc oxide (IZO). The light-shielding layer BM is, forexample, a conductive layer having a lower resistance than the commonelectrode CE. In one example, the light-shielding layer BM is formed ofa nontransparent metal material such as molybdenum, aluminum, tungsten,titanium or silver. The transparent layers 30 and 40 are insulatinglayers formed of, for example, an organic material such assiloxane-based resin or fluorine-based resin. The alignment films AL1and AL2 are horizontal alignment films having an alignment restrictionforce substantially parallel to the X-Y plane. In one example, thealignment films AL1 and AL2 are provided with alignment treatment alongthe first direction X. Note that the alignment treatment may be rubbingtreatment or photo-alignment treatment.

Regarding a reflective index, the transparent substrates 10 and 20 havereflective indexes n10 and n20, respectively. The transparent layers 30and 40 have refractive indexes n30 and n40. The refractive indexes n30and n40 are less than the refractive indexes n10 and n20. In oneexamples, the transparent layers 30 and 40 are formed of the samematerial, and the refractive indexes n30 and n40 are equal. Being“equal” here is not limited to a case where a refractive indexdifference is zero but includes a case where a refractive indexdifference is less than or equal to 0.03. For example, the refractiveindexes n10 and n20 are about 1.5, and the refractive indexes n30 andn40 are greater than or equal to 1.0 but less than or equal to 1.41.

In the example shown in FIG. 3, the main surface 10B of the transparentsubstrate 10 is in contact with air. However, another transparent layerhaving an equal refractive index to the transparent layer 40 may bedisposed on the entire surface of the main surface 10B. In addition,another transparent layer having an equal refractive index to thetransparent layer 30 may be disposed on the entire surface of the mainsurface 20A of the transparent substrate 20.

FIG. 4 is a plan view showing one configuration example of the displaypanel PNL shown in FIG. 1. Here, the explanation will be focused on fourpixels PX1 to PX4 arrayed in a matrix. Scanning lines G1 to G3 extendalong the first direction X and are disposed at intervals along thesecond direction Y. Signal lines S1 to S3 extend along the seconddirection Y and are disposed at intervals along the first direction X.The pixels PX1 to PX4 correspond to regions partitioned by the scanninglines G1 to G3 and the signal lines S1 to S3. The pixels PX1 and PX3 areadjacent to each other in the first direction X and are closer to thelight-emitting element LD than the pixel electrodes PX2 and PX4. Thepixel PX1 includes a switching element SW1 and a pixel electrode PE1.Similarly, the pixels PX2 to PX4 include switching elements SW2 to SW4,respectively, and pixel electrodes PE2 to PE4, respectively. The pixelelectrodes PE1 and PE2 are disposed at an interval along the seconddirection Y. The pixel electrodes PE1 and PE3 are disposed at aninterval along the first direction X. The pixel electrodes PE1 and PE3are close to the light-emitting element LD, and the pixel electrodes PE2and PE4 are away from the light-emitting element LD.

The transparent layer 30 is continuously disposed over the pixels PX1 toPX4. That is, the transparent layer 30 overlaps the scanning lines G1 toG3, the signal lines S1 to S3, the switching element SW1 to SW4 and thepixel electrodes PE1 to PE4. Although not described in detail, thetransparent layer 30 is disposed over the entire region of the displayportion DA in the second substrate SUB2.

The transparent layer 40 has transparent layers 41 to 44 disposedrespectively in the pixels PX1 to PX4. In the illustrated example, thetransparent layers 41 to 44 are formed in an island shape extendingalong the second direction Y and are apart from one another. Forexample, the transparent layers 41 and 43 are disposed at an intervalIV1 in the first direction X, and the transparent layers 42 and 44 aredisposed at an interval IV2 in the first direction X. The interval IV1is less than the interval IV2. The transparent layers 41 and 42 aredisposed at an interval along the second direction Y, and thetransparent layers 43 and 44 are disposed at an interval along thesecond direction Y. Note that the transparent layers 41 and 42 may becontinuously formed, and similarly, the transparent layers 43 and 44 maybe continuously formed.

The transparent layer 41 overlaps the pixel electrode PE1, and thetransparent layer 42 overlaps the pixel electrode PE2. The transparentlayer 41 has a larger area than the transparent layer 42. Therefore, anarea in which the transparent layer 41 overlaps the pixel electrode PE1is greater than an area in which the transparent layer 42 overlaps thepixel electrode PE2. Similarly, the transparent layers 43 and 44 overlapthe pixel electrodes PE3 and PE4, respectively. The area in which thetransparent layer 41 overlaps the pixel electrode PE1 is equal to anarea in which the transparent layer 43 overlaps the pixel electrode PE3,and the area in which the transparent layer 42 overlaps the pixelelectrode PE2 is equal to an area in which the transparent layer 44overlaps the pixel electrode PE4.

When an installation area per pixel is defined as an area overlappingthe pixel electrode PE in planar view, for example, in the first pixelPX, the transparent layer 30 overlaps almost the entire pixel electrodePE1, whereas the transparent layer 41 overlaps a part of the pixelelectrode PE1, and the installation area of the transparent layer 41 isless than the installation area of the transparent layer 30. The sameapplies to the other pixels PX2 to PX4.

The light-shielding layer BM is formed in a lattice shape. Thelight-shielding layer BM overlaps the scanning lines G1 to G3, thesignal lines S1 to S3 and the switching elements SW1 to SW4. Inaddition, the light-shielding layer BM overlaps a pair of end portionsE1 of the transparent layer 41, a pair of end portions E2 of thetransparent layer 42, a pair of end portions E3 of the transparent layer43, and a pair of end portions E4 of the transparent layer 44. These endportions E1 to E4 are end portions extending along the first directionX.

FIG. 5 is a cross-sectional view showing one configuration example ofthe display device DSP of the present embodiment. Note that, regardingthe display panel PNL, only main parts are illustrated. The emittedlight from the light-emitting element LD will be explained withreference to FIG. 5.

The light-emitting element LD emits light L1 toward the side surfaceE11. Since an air layer is present between the light-emitting element LDand the side surface E11, the light L1 emitted from the light-emittingelement LD is refracted at the side surface E11 and enters thetransparent substrate 10. Light traveling toward the main surface 10B ofthe light L1 entering the transparent substrate 10 is reflected at theinterface between the transparent substrate 10 and an air layer. Inaddition, light traveling toward the light-shielding layer BM of thelight L1 entering the transparent substrate 10 is reflected at thelight-shielding layer BM. Furthermore, light traveling toward thetransparent layer 40 of the light L1 entering the transparent substrate10 is reflected at the interface between the common electrode CE and thetransparent layer 40 and does not reach the alignment film AL1, theliquid crystal layer LC and the second substrate SUB2. As describedabove, close to the side surface E11 (or in a region in which thetransparent layer 40 is present), the light L1 travels inside thetransparent substrate 10 while being repeatedly reflected. Lighttraveling toward a region in which the transparent layer 40 is notpresent, that is, a region in which the common electrode CE and thealignment film AL are in contact with each other of the traveling lightL1 enters the liquid crystal layer LC.

As explained with reference to FIG. 4, the installation area per pixelof the transparent layer 40 is small in the region close to thelight-emitting element LD as compared with the region away from thelight-emitting element LD. Therefore, while the entry to the liquidcrystal layer LC of the light L1 from the light-emitting element LD issuppressed in the region close to the light-emitting element LD, theentry to the liquid crystal layer LC of the light L1 is promoted in theregion away from the light-emitting element LD. In the region close tothe light-emitting element LD, not all the entry to the liquid crystallayer LC of the light L1 is suppressed, but the light L1 enters theliquid crystal layer LC from a region in which the transparent layer 40does not overlap the pixel electrode PE as shown in FIG. 4.

Light traveling toward the transparent layer 30 of the light enteringthe liquid crystal layer LC is reflected at the interface between thealignment film AL2 and the transparent layer 30. The light L1 enteringthe liquid crystal layer LC is transmitted through the pixel in thetransparent state and is scattered in the pixel in the scattering state.The display device DSP can be observed from an observation position VP1on a main surface 10B side and can also be observed from an observationposition VP2 on a main surface 20A side. In addition, regardless ofwhether the display device DSP is observed from the observation positionVP1 or the observation position VP2, the background of the displaydevice DSP can be observed via the display device DSP.

According to the present embodiment, in the region in which thetransparent layer 40 is present, the light traveling inside thetransparent substrate 10 does not enter the alignment film AL1 buttravels inside the transparent substrate 10. Accordingly, undesiredabsorption or scattering in the alignment films AL1 and AL2 can besuppressed, and a decrease in the use efficiency of the light from thelight-emitting element LD can be suppressed.

In particular, when attention is focused on the luminance distributionof the light from the light-emitting element LD, the luminance tends todecrease rapidly as the light travels away from the light-emittingelement LD. One cause of the decrease in luminance is undesiredabsorption. Therefore, the decrease in luminance can be suppressed bysuppressing absorption in the alignment films AL1 and AL2.

In addition, the pixel electrode PE, the capacitance electrode 23, theswitching element SW, the signal line S and the scanning line G arelocated between the transparent layer 30 and the transparent substrate20. Since the light traveling toward the transparent layer 30 of thelight L1 entering the liquid crystal layer LC is reflected at theinterface between the alignment film AL2 and the transparent layer 30,undesired absorption and scattering in the pixel electrode PE, thecapacitance electrode 23, the switching element SW, the signal line Sand the scanning line G are suppressed. Therefore, according to thepresent embodiment, degradation of display quality can be suppressed.

Furthermore, the region in which the transparent layer 40 overlaps thepixel electrode PE corresponds to a region where the light from thelight-emitting element LD hardly enters the alignment film AL1 and theliquid crystal layer LC, and the region in which the transparent layer40 does not overlap the pixel electrode PE (or in the region between thetransparent layers 40 which are adjacent to each other) corresponds to aregion in which the light from the light-emitting element LD enters theliquid crystal layer LC via the alignment film AL1. The installationarea per pixel of the transparent layer 40 is small in the region closeto the light-emitting element LD as compared with the region away fromthe light-emitting element LD. Therefore, while the entry to the pixelof the light is suppressed in the region close to the light-emittingelement LD, the entry to the pixel of the light is promoted in theregion away from the light-emitting element LD. As described above, thelight from the light-emitting element LD attenuates as the light travelsaway from the light-emitting element LD. The luminance of the light inthe region close to the light-emitting element LD is referred to thefirst luminance, and the luminance of the light in the region away fromthe light-emitting element LD is referred to as the second luminance.The second luminance is less than the first luminance. The installationarea of the transparent layer 40 installed in the pixel PX1 shown inFIG. 4 is greater than the installation area of the transparent layer 40installed in the pixel PX2. Therefore, the area of a region in which thelight can enter the pixel PX1 is less than the area of a region in whichthe light can enter the pixel PX2. On the other hand, the firstluminance of the light entering the pixel PX1 is greater than the secondluminance of the light entering the pixel XP2. Therefore, the amounts ofillumination light in the pixel PX1 and the pixel PX2 can be equalized.

In the configuration example shown in FIGS. 1 to 5, the transparentsubstrate 10 corresponds to the first transparent substrate, thealignment film AL1 corresponds to the first alignment film, thetransparent layer 40 corresponds to the first transparent layer, thetransparent substrate 20 corresponds to the second transparentsubstrate, the transparent layer 30 corresponds to the secondtransparent layer, the alignment film AL2 corresponds to the secondalignment film, the pixel electrode PE1 corresponds to the first pixelelectrode, and the pixel electrode PE2 corresponds to the second pixelelectrode. Note that the scanning line G, the signal line S, theswitching element SW and the pixel electrode PE may be disposed in thefirst substrate SUB1, and the common electrode CE may be disposed in thesecond substrate SUB2.

Next, other configuration examples of the present embodiment will beexplained.

FIG. 6 is a cross-sectional view showing another configuration exampleof the display device DSP shown in FIG. 5. The configuration exampleshown in FIG. 6 is different from the configuration example shown inFIG. 5 in that the first substrate SUB1 includes an insulating film 50.The transparent layer 40 is formed on the main surface 10A and iscovered with the insulating film 50. The common electrode CE is locatedbelow the insulating film 50 and is covered with the alignment film AL1.The insulating film 50 is, for example, an organic insulating filmformed of an organic material such as acrylic resin. A lower surface ofthe insulating film 50 which is in contact with the common electrode CEis planarized. In the illustrated example, the transparent layer 40 islocated between the common electrode CE and the transparent substrate10.

Also in this configuration example, similar effects to those of theconfiguration example shown in FIG. 5 can be obtained. In addition,since the transparent layer 40 is located between the transparentsubstrate 10 and the common electrode CE, as compared with a case wherethe transparent layer 40 is located between the common electrode CE andthe alignment film AL1, the common electrode CE approaches the pixelelectrode PE along the third direction Z, and a decrease in the electricfield strength between the pixel electrode PE and the common electrodeCE can be suppressed.

FIG. 7 is a cross-sectional view showing another configuration exampleof the display device DSP shown in FIG. 5. The configuration exampleshown in FIG. 7 is different from the configuration example shown inFIG. 5 in that the pixel electrode PE is formed on the transparent layer30. The transparent layer 30 is located between the switching element SWand the pixel electrode PE.

Also in this configuration example, similar effects to those of theconfiguration example shown in FIG. 5 can be obtained. In addition,since the transparent layer 30 is located between the transparentsubstrate 20 and the pixel electrode PE, as compared with a case wherethe transparent layer 30 is located between the pixel electrode PE andthe alignment film AL2, the pixel electrode PE approaches the commonelectrode CE along the third direction Z, and a decrease in the electricfield strength between the pixel electrode PE and the common electrodeCE can be suppressed.

Note that, although the insulating film 21 is located between thetransparent substrate 20 and the transparent layer 30 in the illustratedexample, the insulating film 21 may be omitted.

FIG. 8 is a cross-sectional view showing another configuration exampleof the display device DSP shown in FIG. 5. The configuration exampleshown in FIG. 8 corresponds to an example where the first substrate SUB1shown in FIG. 6 and the second substrate SUB2 shown in FIG. 7 arecombined.

Also in this configuration example, similar effects to those of theconfiguration example shown in FIG. 5 can be obtained. In addition,since the transparent layer 30 and the transparent layer 40 are notlocated between the pixel electrode PE and the common electrode CE, thecommon electrode CE and the pixel electrode PE approach each other alongthe third direction Z, and a decrease in the electric field strengthbetween the pixel electrode PE and the common electrode CE can befurther suppressed.

Next, other configuration examples of the transparent layer 40 will beexplained with reference to FIGS. 9 and 10.

FIG. 9 is a plan view showing another configuration example of thetransparent layer 40 shown in FIG. 4. The configuration example shown inFIG. 9 is different from the configuration example shown in FIG. 4 inthat the transparent layers 43 and 44 are close to the signal line S2.Note that the transparent layers 41 to 44 may be continuously formed.

FIG. 10 is a plan view showing another configuration example of thetransparent layer 40 shown in FIG. 4. The configuration example shown inFIG. 10 is different from the configuration example shown in FIG. 4 inthat the transparent layer 41 is close to the signal line S1 and thetransparent layer 44 is close to the signal line S2. Note that thetransparent layers 42 and 44 may be continuously formed.

Also in the configuration examples shown in FIGS. 9 and 10, similareffects to those described above can be obtained.

As described above, according to the present embodiment, a displaydevice which can suppress degradation of display quality can beprovided.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the inventions. Indeed, the novel embodiments described hereinmay be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the embodimentsdescribed herein may be made without departing from the spirit of theinventions. The accompanying claims and their equivalents are intendedto cover such forms or modifications as would fall within the scope andspirit of the inventions.

An example of the display device obtained from the configurationsdisclosed in the specification will be appended below.

(1)

A display device including:

a first substrate including a first transparent substrate having a sidesurface and a main surface, a first alignment film disposed along themain surface, and a first transparent layer located between the firsttransparent substrate and the first alignment film;

a second substrate including a second transparent substrate, a scanningline, a signal line crossing the scanning line, a switching elementelectrically connected to the scanning line and the signal line, and apixel electrode electrically connected to the switching element;

a liquid crystal layer held between the first substrate and the secondsubstrate and containing a stripe-shaped polymer and liquid crystalmolecules; and

a light-emitting element opposed to the side surface, wherein

the first transparent layer overlaps a part of the pixel electrode andhas a lower refractive index than the first transparent substrate.

(2)

The display device described in (1), wherein the first transparent layerhas a refractive index of greater than or equal to 1.0 but less than orequal to 1.41.

(3)

The display device described in any one of (1) and (2), wherein

the first substrate further includes a common electrode opposed to thepixel electrode, and

the first transparent layer is located between the common electrode andthe first alignment film.

(4)

The display device described in any one of (1) and (2), wherein

the first substrate further includes a common electrode opposed to thepixel electrode, and

the first transparent layer is located between the common electrode andthe first transparent substrate.

(5)

The display device described in any one of (1) to (4), wherein

the second substrate further includes a second alignment film contactingthe liquid crystal layer, and a second transparent layer located betweenthe switching element and the second alignment film, and

the second transparent layer has an equal refractive index to the firsttransparent layer.

(6)

The display device described in (5), wherein the second transparentlayer is located between the pixel electrode and the second alignmentfilm.

(7)

The display device described in (5), wherein the second transparentlayer is located between the switching element and the pixel electrode.

(8)

A display device including:

a first substrate including a first transparent substrate having a sidesurface and a main surface, and a first alignment film disposed alongthe main surface;

a second substrate including a second transparent substrate, a scanningline, a signal line crossing the scanning line, a switching elementelectrically connected to the scanning line and the signal line, a pixelelectrode electrically connected to the switching element, a secondalignment film located on the pixel electrode, and a second transparentlayer located between the switching element and the second alignmentfilm;

a liquid crystal layer held between the first substrate and the secondsubstrate and containing a stripe-shaped polymer and liquid crystalmolecules; and

a light-emitting element opposed to the side surface, wherein

the second transparent layer overlaps the pixel electrode and has alower refractive index than the first transparent substrate.

(9)

A display device including:

a first substrate;

a second substrate;

a liquid crystal layer held between the first substrate and the secondsubstrate and containing a stripe-shaped polymer and liquid crystalmolecules;

a light-emitting element; and

pixels arrayed in a matrix, wherein

the first substrate includes a first transparent substrate having a sidesurface opposed to the light-emitting element, a first alignment filmcontacting the liquid crystal layer, and a first transparent layerlocated between the first transparent substrate and the first alignmentfilm,

the second substrate includes a second transparent substrate, a secondalignment film contacting the liquid crystal layer, and a secondtransparent layer located between the second transparent substrate andthe second alignment film,

the first transparent layer and the second transparent layer areinsulating layers, and

an installation area per pixel of the first transparent layer is lessthan an installation area per pixel of the second transparent layer.

(10)

The display device described in (9), wherein

the second substrate further includes a first pixel electrode disposedin a first pixel close to the light-emitting element, and a second pixelelectrode disposed in a second pixel away from the light-emittingelement, and

an area in which the first transparent layer overlaps the first pixelelectrode is less than an area in which the first transparent layeroverlaps the second pixel electrode.

(11)

The display device described in (10), wherein

the first substrate further includes a common electrode opposed to thefirst pixel electrode and the second pixel electrode, and

the first transparent layer is located between the common electrode andthe first alignment film.

(12)

The display device described in (10), wherein

the first substrate further includes a common electrode opposed to thefirst pixel electrode and the second pixel electrode, and

the first transparent layer is located between the common electrode andthe first transparent substrate.

(13)

The display device described in (9), wherein

the second substrate further includes a scanning line, a signal linecrossing the scanning line, a switching element electrically connectedto the scanning line and the signal line, and a pixel electrodeelectrically connected to the switching element, and

the scanning line, the signal line and the switching element are locatedbetween the second transparent substrate and the second transparentlayer.

(14)

The display device described in (13), wherein

the second transparent layer is located between the pixel electrode andthe second alignment film.

(15)

The display device described in (13), wherein the second transparentlayer is located between the switching element and the pixel electrode.

(16)

The display device described in any one of (9) to (15), wherein thefirst transparent layer and the second transparent layer each have alower refractive index than the first transparent substrate.

(17)

The display device described in (16), wherein the first transparentlayer and the second transparent layer each have a refractive index ofgreater than or equal to 1.0 but less than or equal to 1.14.

(18)

The display device described in (17), wherein the first transparentlayer and the second transparent layer have an equal refractive index.

(19)

The display device described in (9), wherein

the side surface extends along a first direction, and

the first transparent layers are disposed at intervals along the firstdirection.

(20)

The display device described in (19), wherein the interval on a sideclose to the light-emitting element is less than the interval on a sideaway from the light-emitting element.

What is claimed is:
 1. A display device comprising: a first substrate; asecond substrate; a liquid crystal layer held between the firstsubstrate and the second substrate and containing a stripe-shapedpolymer and liquid crystal molecules; a light-emitting element; andpixels arrayed in a matrix, wherein the first substrate comprises afirst transparent substrate having a side surface opposed to thelight-emitting element, a first alignment film contacting the liquidcrystal layer, and a first transparent layer located between the firsttransparent substrate and the first alignment film, the second substratecomprises a second transparent substrate, a second alignment filmcontacting the liquid crystal layer, and a second transparent layerlocated between the second transparent substrate and the secondalignment film, the first transparent layer and the second transparentlayer are insulating layers, and an installation area per pixel of thefirst transparent layer is less than an installation area per pixel ofthe second transparent layer.
 2. The display device of claim 1, whereinthe second substrate further comprises a first pixel electrode disposedin a first pixel close to the light-emitting element, and a second pixelelectrode disposed in a second pixel away from the light-emittingelement, and an area in which the first transparent layer overlaps thefirst pixel electrode is less than an area in which the firsttransparent layer overlaps the second pixel electrode.
 3. The displaydevice of claim 2, wherein the first substrate further comprises acommon electrode opposed to the first pixel electrode and the secondpixel electrode, and the first transparent layer is located between thecommon electrode and the first alignment film.
 4. The display device ofclaim 2, wherein the first substrate further comprises a commonelectrode opposed to the first pixel electrode and the second pixelelectrode, and the first transparent layer is located between the commonelectrode and the first transparent substrate.
 5. The display device ofclaim 1, wherein the second substrate further comprises a scanning line,a signal line crossing the scanning line, a switching elementelectrically connected to the scanning line and the signal line, and apixel electrode electrically connected to the switching element, and thescanning line, the signal line and the switching element are locatedbetween the second transparent substrate and the second transparentlayer.
 6. The display device of claim 5, wherein the second transparentlayer is located between the pixel electrode and the second alignmentfilm.
 7. The display device of claim 5, wherein the second transparentlayer is located between the switching element and the pixel electrode.8. The display device of claim 1, wherein the first transparent layerand the second transparent layer each have a lower refractive index thanthe first transparent substrate.
 9. The display device of claim 8,wherein the first transparent layer and the second transparent layereach have a refractive index of greater than or equal to 1.0 but lessthan or equal to 1.14.
 10. The display device of claim 9, wherein thefirst transparent layer and the second transparent layer have an equalrefractive index.
 11. The display device of claim 1, wherein the sidesurface extends along a first direction, and the first transparentlayers are disposed at intervals along the first direction.
 12. Thedisplay device of claim 11, wherein the interval on a side close to thelight-emitting element is less than the interval on a side away from thelight-emitting element.